Purpose of review: At current safety levels, with adverse events from transfusions being relatively rare, further progress in risk reductions will require large-scale investigations. Thus, truly prospective studies may prove unfeasible and other alternatives deserve consideration. In this review, we will try to give an overview of recent and historical developments in the use of blood donation and transfusion databases in research. In addition, we will go over important methodological issues.
Recent findings: There are at least three nationwide or near-nationwide donation/transfusion databases with the possibility for long-term follow-up of donors and recipients. During the past few years, a large number of reports have been published utilizing such data sources to investigate transfusion-associated risks. In addition, numerous clinics systematically collect and use such data on a smaller scale.
Summary: Combining systematically recorded donation and transfusion data with long-term health follow-up opens up exciting opportunities for transfusion medicine research. However, the correct analysis of such data requires close attention to methodological issues, especially including the indication for transfusion and reverse causality.